Containers in which a fibrous sheet material is sealed to itself or a polymeric film sheet have been used in a variety of different applications. One such application is directed to a container for packaging articles that are to be sterilized.
Sterilizable containers in the form of pouches or bags, sealed trays, and envelopes are popular vehicles for storing and transporting sterile articles, including instruments, dressings, drapes, etc. Typically, such containers include sheet of a fibrous breathable material that is both a microbe barrier and is gas pervious. After the article has been sealed in the container, the container is treated with a sterilizing gas that is introduced into the interior of the container through the fibrous breathable material. The porous characteristics of the fibrous breathable material allows a sterilizing medium, such as sterilizing gas (e.g., steam, ethylene oxide, etc.) to pass into and out of the container, while forming a sterile barrier against bacteria or other contaminants.
One such container comprises a pouch or bag comprising a polymeric sheet and a sheet of a fibrous breathable material, such as paper or TYVEK®, that are positioned face-to-face and sealed to each other along their common peripheral edges to form seams defining a pouch. The pouch or bag is typically opened by cutting or peeling off of the fibrous breathable material.
Another example of a sterilizable container comprises a container in which two sheets of polymeric film are sealed to each other along peripheral edges to form seams defining a pouch. The pouch includes an access opening formed in one of the film sheets through which a sterilizing gas can be introduced into the interior space of the pouch. In this type of container, the access opening is covered by the fibrous breathable material, also referred to as a “header,” that is sealed to the outer surface of the pouch. These types of containers may be opened via a tear notch located at one end of the pouch that can be used to linearly tear the film and gain access to the contents of the pouch.
Alternatively, the fibrous breathable material can be removed by peeling it away from the film sheet to thereby gain access to the sterilized article through the access opening. In order for the header to be easily removed to gain access to the opening, the fibrous breathable material is typically coated so that the material is peelable from the surface of the package. Unfortunately, the presence of a coating results in a substantial decrease in the porosity, and hence breathability of the breathable material. This in turn results in longer sterilization times to ensure that an effective amount of sterilization gas is introduced into the package. In order to address this problem, packages have been developed in which the size of the opening is greatly increased to thereby improve the overall breathability of the package. However, such designs necessarily require an increased amount of breathable material in order to cover the opening, which results in higher production costs.
Another common package for packaging of medical devices is a blister-type package in which a sheet of the fibrous breathable material is sealed to the peripheral edge of a tray to form a lidding. After an article has been sealed in one of these types of packages, a sterilizing gas can then be introduced into the interior of the package through the breathable membrane. These types of packages are typically opened by either cutting or tearing off of the fibrous breathable material in order to gain access to the article packaged therein.
All of the aforementioned containers present disadvantages. First, in the packaging of sterilized articles, it is important to maintain a sterile and aseptic presentation upon opening of the container. Tyvek®, which is widely used as a microbe barrier material, is a nonwoven sheet material made of individual fibers that are thermally bonded to each other to form a coherent fabric. Opening of a container that includes a fibrous breathable material along a seam or by cutting may result in the creation of small fibers that may be deposited on the sterilized article. In addition, a problem that has been associated with the use of a coated breathable material is the release of particulate matter from the coating itself, or from the breathable material as it is removed from the container.
The release of such particulate matter and fibers can compromise the sterile field, and is therefore unacceptable.
Accordingly, there is a need for improved containers for packaging and sterilizing of articles, and in particular, for packaging and sterilizing of articles, devices and instruments to be used in medical applications.